Rotary disk wood chipper



Sept. 4, 1951 J. R. DUNBAR ROTARY DISK wooD'" CHIPPER Filed April 5, 1947 3 Sheets-Sheet l o 5 w 1 1 i m a y 2 9 5 5 w 2 2 /l\ 1 2 3 55 w a m QIIJ w L 82 2. %3 4 I INVENTCf? JAMES ROBERT DUNBAR Z /ZM ATTORNEY Sept. 4, 1951 J R, DUNBAR 2,566,721

ROTARY DISK woon CHIPPER Filed April 5, 1947 a Sheets-Sheet 2 INVENTOR JAMES ROBERT DUNBAR jaw AT TORNEY Sept. 4, 1951 J DUNBAR 2,566,721

ROTARY DISK WOOD CHIPPER I Filed April 5, 1947 5 Sheets$heet 3 IN VEN TOR JAMES ROBERT DUNBAR ATTORNEY Fatented Sept. 4, 1 951 ApplicationApi-il 1947, Serial palis ,illll ini My invention relatesto improvements-inchip pers which are particularlyadaptedrfor making chips from wood-for pulp-inthe productionoipaperk H T Where the chips produced are of irregular size the resulting pulp from the digestion -of;-the wood is imperfectsince small chips 'will' be digestedtoo quickly and large chips :will not be properly ,digested-unlessthe digesting processfis continued-a longer'timethan is necessary -for the digestion of the-regular size chips, :When the=pulp-wi1l-be of' poor Q010111.--"- I Y My The conventional chipper isgobjectionableand' mechanically defective in many ways-gsome of which are as follows: .Only one feedspo'ut .is-jprovided in which thelogs are fedby gravity at,approximately 55, degreesjrom the horizontal; ,the knife cuts in a vertical,planeLanisince the logs are apt to tiltlto adifierentang-le .tonthe angle; of the bottom wall ,of the spout, due a to the shockf ot, the descending knife,v any cutting, severed trgrn said log may'vary-inthicknessiromrthe start'pi the cut to the .end -ofjsaid "out flnh srlflgfdistlll bh ance islargely-responsible.ior uneven length f chips and alsoin part for the developmentpi long ribbon orshaving from one sidetof the logr which ribbon passes betweentherotary lgnifiegan d the bed knife at the; bottomhoi the spout a gijhalls to b irom t ,ba ec .v t e chips from the-chipper are required to bescre'ened and passed, through a chip: breakenwhich, com;- minutes mu h of.v the materials to a.,,fi nj d ZiSiQI 6r. are passed ih h re hip erga ii allir again screened. {Ifhelshock imparted to thechip-f per Shaft afi r i lill ljqy ifi l stant displacement ogthe log froin its .55 degree;

a h wh a s n new he s i t-i; .1 3? orqu during cut ng. and the i ht .fqrq fi be: ween we c use i uch s r gus ib at psjc t e machine that an'extremely heayy foundation must beprovided with standl the strains result ff ing therefrom. The present 1n un o m intsi i t' ip nee .iromiindy slice taken from; a. block ,-sha11,.extend aeritiillg across. said block rtoprevent the ribbon zorsshaving which especially towards thetrailingendof the block -is frequently, carriedwbetweent the; slicing knife and bed knife of -theaconventional design;;

iifi 'wo d th tsthe chip will-be fiqb te i lly;

materiaLso thatvtheidiges il Dm O-Q ,F

Columpia, Canada th t z u n-" t sr qtotsh chipper; and-all-zmatenial cutnniustrpass 'through the disc opening =invfrontrof eaJchsliciiig "knife. A further obj ectzis to proiiidethat orie side: of th'e logrbeing cut shallrremaiii firnily'in cohtact'ifiith thespout ;in-- .-Which\v itfiisrplaced throiiglioht'the cutting 1 of said log einkorder-r that z'all *the 1 c'uts madei b-y a knife. shallibemarallekarfd'the"thick ness of the sl-ices i'cut remamvconstantr 'n still" further; obj ect -is- -to :prmide means for breakingr ny liced ma teria-l w-hichwhas failed tobreak down to a suitable size-pnfleav-ing-:thetkriife. Still further objects are; toprovide; that? therlogsticiit shall'be at a mere acuteIanglefroirrthe hciiizontal than, the eonyentipnalkmaehinaso that "the s u t-on t -i uttinesdziscwcr imtorsshan be reduced, and-toprpyideya plurality of ieedispouts to-the machine tl a t at?tull -parts,ioff'a-revclntion-some :knivesmilli engagement with' -lo gs rb Q t..w r b 5; su stantiate on t rque will be maintai-ned,- and -to i provide a heavy body of m h n reachekn es z i 'h itsti ail i i pactoi? aikn-ife'against itgwo lgwill rrotengender vibraticnrin the [body of; the kniie carrying disc; Since-vibration isgreduced agwminimum and is constant-;-rather than pulsating, ,;--my' chipper sicapable of subs tantiallylztwice the am qunt =.'WOIk::fOI':- a given Power u fio pr' I w ll l :be een t t; Since he" -Q ri5s 1 Q q e zan' is-mmrab about a-NerticaLaxis, anymaterial -fed into-the nalw e so e i- 2-isamlanir sh wi eth x h a n taken on the linej of' ,-Figure 1; g i n l y eq riew v encee 17 0f Figure -1 -showing thestationany chip: breaker" s wqizm s t t ;-is: an enlarged;-pla n; iew'of the-motor n' r rz h run emd 6 sy ta sectiona v e e 'thea hinpenzcotntane d se et s ows? 2 Fige ibis-ga transye spoutzshoezz" s. V H I:

fi e' isaa diagrammatic fviewi'showihg thetraverse-ofa kniiewacress ithmteed {opening an In th'e drawings like! characters-inf sreference 1 indicate correspondin grc-partsiiireachi-figure. it: 4 The: numeral dxvindicatesgenerallyiahylindricfil whichs freqnentlw deyelcpsin'ithe -egnventionalv 65 base havingrasicylindricalwwall fiin'fi'which'itwo:

I 3 is provided at its upper end with a heavy rotor l4, a cone spreader [5, a chip breaker disk I6 and a driving pulley l1, all of which are secured thereto. The casing 8 is provided with a top plate I 9 which is fitted in this instance with three tan ential openings '29 and log feed spout shoes 2| therefor.

The rotor I4 consists of a disk 22 having a heavy peripheral rim 23. with four tangentially arranged slots 25 having a' leading edge 28. and a trailing edge 21. "The phrase tangentially arranged means-that the blade. edge is arranged, relative to a quadrant of the rotor solthat the edge is substantially normal to the leading radius defining a quadrant and substantially parallelto the trailing radius of thatq'uadrant. This "will be obviou from an inspection. of Figure 4. in the angularity of the blade is permissible the angle must be such that the inner end of the knife leads the outer end by a substantial amount. From the trailing edge 21 of each slot an angular recess 28 is provided to receive a'knife 29 having a cutting edge 39 wh ch extends partially across the slot 25 and upwardly above the upper surface plane 3| of the disk 22, the knife being suitably anchored in its recess by bolts 33, one only shown in Figure 6. --The knives 29 are each set at a tangent to the periphery of the rotor, so that the inner end of each cutting edge engages the work in the feed opening at an appreciable interval before the outer end of said cutting edge passe beyond said opening. The preferred setting as herein shown, is for the cutting edge of each knife to be at an angle of fifty degrees to a radial line cutting through the disk and the centre of said cutting edge, the inner end of said edge leading the outer end as the disk is rotated. The length of each cutting edge when so set, will require to be at least two and a half times the maximum radial dimen sion of the feed opening, the efl'ective'cutting length of said knife in the example shown is around eighty percent longer than the greatest dimension across the feed openin g'.- -'The'1ines A, B, C, D; E and 'F represent different positions of each knife 29 when traversing a cutting opening 20, the lines C and'D each being adjacent the greatest dimensionofsaid opening, see Figure 9. That portion of the disk which is immedie the cutting stroke. The projection of the cutting" edge of the knife. has a definite bearing on the cross sectional area of the inertia body '36 "in as much-as that if the body is light, vibration will be heavy with resultant loss of power; efliciency of the machine and durabilityof same. On the assumption that the machine. is cutting The disk is provided While some var ation 4. soft wood and the disk is of iron, then the cross sectional area of the inertia body should be in square inches not less than forty-five times the offset of the cutting edge of the knife in inches above the upper face of the disk. In the present instance the cross sectional area of the inertia body 35 is thirty-six inches and the cutting edge 39 of the knife 29 is offset vertically three-quarter of an inch, the ratiobetween them being 48 to 1. Some'wood is softer than others, so that with softer wood to out, somewhat less than 48 to 1 would be atisfactory. Obviously if a lighter metal than iron were used in the construction of the rotor, a heavier inertia body would be required to reduce. the vibration to a minimum. Forward of the inertia body 36 an overhang 38 is provided as a support for the front edge of the knife.

Each spout shoe 2| consists of an inclined tube 40, here shown as rectangular in cross section, having a base flange "4! by which it is secure to the top plate i9 surrounding one of the open; ings 29, and secured to the said shoe at its lead ing end 42 and to its outer side 43 are stationary bed knives '44 and 45 respectively, both of which are adjustable towards the rotating knives 29', each outer knife 45 forms an abutment for the pulp log 41 shown in dotted line in Figure 8; against the radial thrustbf the rotating knife and each end knife forms an abutment for the lead ng end of said pulp log, so'that each log will be held firmly in position within the; shoe by the pressure applied to it by the coacting rotary knife 29. a

Extending inwardly fromthe peripheral wall 9 are circumferentially arranged sets of chip breaker finger 50, preferably three fingers to, each set, spaced apart vertically and with each adjacent lower finger being set in advance "of the one above it as 59A,"5DB and 590, see Figure 3. Pivotally mounted .at spaced intervals on the rim of the chip breaker disk |6,,are sets of breaker hammers 52, in which one hammerof a set is above the disk and the other hammer is below, which hammers are adapted to pass between the fingers 50A and 50B and 50B and .590, as indicated in Figure '3 by dotted line arrows 55. The cone I5 is of such size as to cause all chips to pass between the peripheryof the disk l6 and the casing wall 9, so that if a portion; of a slice cut by the knives 29 is too big to drop, freely through the annularinterspace between said disk and the casing-wall, it will engage one of the ets of breaker fingers a'ndbe engaged, by one or more of the sets" of hammers52 to; reduceit to appropriate size. v

In operation, logs or slabs of wood are put into the spouts and slide into the position shown. in dotted line in Figure 8, the shaft I3 .is rotated.- at suitable speed and in appropriate direction. to cause the knives 29 to slice cut'diagonal. grained slices from the logs progressively, the tangential disposition of the knives 29 causes. the wood to be firmly held against theend and.

' front stationary knives 44 and 45 and the lower.

outer edge of the log to remain in, contact on the lower inclined plane56 of the, spout 40 and of the spout shoe 2!, thus'insuring that each cut will be clean" and extend completely inf'a" single plane through the wood; leaving no ribbon? strip attaching to the log, 'such'as is commonj with the conventional chipper having knives,

cutting in a vertical plane. As each slice isbeing' cut, "it strikes the overhang 38-and breaks prog-ressiveiy into very short sections of a lengthslightly greater than the length of the grain in them. These sections of diagonal grain material pass through the slots 25 and are thrown violently into contact with the concave area of the casing wall 9 which breaks them into short piece of ubstantially constant cross sectional dimensions. Any of the broken pieces which may be longer than desired are carried to the outer edge of the disk l6 and are deposited onto the breaker fingers and are subsequently hit by 'the swinging hammers 52, being broken down between said hammers and the fingers 59A, 50B and 50C, finally dropping onto the inclined bottom wall In to immerge through the discharge opening 4, without being broken down to such fine division as to require screening.

The number of knives 29 in the rotor I4 is preferably one less or one more than the number of log spout shoes 2|, so that the several knives will be at different points of engagement with the pulp logs in said spout shoes and the torque upon the shaft incidental to cutting said logs will be substantially constant.

What I claim as my invention is:

A pulp wood chipper comprising a casing having a cover plate provided with a rectangular feed opening; a pulp receiving shoe having an inclined passage communicating with said feed opening; a horizontal rotor below said cover plate; a plurality of straight edged chipper knives mounted on said rotor adapted to sweep across said rectangular feed opening, each knife being located with reference to a quadrant so as to be substantially perpendicular to the leading radius of the quadrant and substantially parallel to the trailing radius of the quadrant, and being offset from the trailing radius by an amount approximating one-half the leading radius, each knife being of a length sufficient completely to traverse the said opening and securely hold a piece of wood being cut in an angle of thereotangular opening and in the pulp receiving shoe.

JAMES ROBERT DUNBAR.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 277,284 Howser May 8, 1883 291,191 Ittner Jan. 1, 1884 398,348 Rabe Feb. 19, 1889 666,211 Shortt Jan. 15, 1901 807,571 Morterud Dec. 19, 1905 1,295,388 Tidmarsh Feb. 25, 1919 1,798,465 Grindle Mar. 31, 1931 1,932,166 Sumner Oct. 24, 1933 1,942,675 Wigger et al. Jan. 9, 1934 1,972,586 Etter et al Sept. 4, 1934 1,980,885 Smith Nov. 13, 1934 2,041,207 Rietz May 19, 1936 2,172,449 Pelot et a1 Sept. 12, 1939 2,174,593 Pelot et a1. Oct. 3, 1939 2,388,799 Payzer et al. Nov. 13, 1945 

